Since that would be very out of character for an American Christian, I would certainly be surprised.
Indeed, American Christians would much prefer to shoot up a Planned Parenthood than a gay nightclub.
The numbers of Americans killed by Christian terrorism vs Islamic terrorism is a bunny hill vs Mt Everest. What a strawman.
Actually, the numbers of Americans killed by domestic terrorism is greater than any foreign terrorism.
Perhaps, if you're really broad with some terms and are counting over the entire history of the US. But if you shorten that time frame to say, the last 100 years, you're going to need a cite for that claim.